Multiple contact miniature diaphragm relay



Filed Nov. 23, 1966 Aug. 1969 I a. a MYATT ETAL 3,460,077

MULTIPLE CONTACT MINIATURE DIAPHRAGM RELAY 2 Sheets-Sheet 1 E. R. MYATTETAL MULTIPLE CONTACT MINIATURE DIAPHRAGM RELAY Filed Nov. 23, 1966 Aug.5, 1969 2 Sheets-Sheet 2 QEW US. Cl. 335-152 2 Claims ABSTRACT OF THEDISCLOSURE A multiple contact electromagnetic relay suitable formounting on a printed wiring board, primarily for crosspoint switching,has a number of scaled contact units mounted magnetically in series. Inthe embodiment described the contact units are of the so-calleddiaphragmrelay type. This arrangement results in a narrow spread ofoperating characteristics, i.e. narrower than the spread found with theindividual single contact units.

This invention relates to multiple contact light current electromagneticrelays incorporating sealed contact devices, i.e. devices having contactmaking members hermetically sealed inside an enclosure. The inventionalso relates to such relays which are suitable for incorporation incrosspoint switching arrays, such as can be used in telephone switchingequipment, and to crosspoint switching arrays incorporating such relays.

According to the invention there is provided a multiple contact lightcurrent electromagnetic relay including two or more sealed contactdevices arranged so that the main magnetic flux paths through all thedevices are in series, and one or more energising coils arranged tooperate the sealed contact devices.

According to the invention there is further provided a multiple contactlight current electromagnetic relay including two or more sealed contactdevices, in which each sealed contact device includes a hermeticallysealed enclosure, a flat resilient plate of electrically andmagnetically conductive material sealed into the enclosure around aperipheral area and having an inwardly extending integral armature whichforms a movable contact member, and a fixed member of magnetically andelectrically conductive material sealed into the enclosure to provide acontact member and magnetic pole piece co-operating with the movablecontact member, in which the sealed contact devices are arranged so thatthe main magnetic flux paths through all the devices, that is throughthe fixed contact member and the movable contact member of each device,are in series, and in which one or more energising coils, external tothe enclosures, surround the fixed contact members.

Embodiments of the invention will now be described, by way of example,with reference to the accompanying drawings, in which:

FIG. 1 shows a sectioned side view of a sealed contact device,

FIG. 2 shows a perspective view of the sealed contact device shown inFIG. 1,

FIG. 3 shows a plan view of a flat plate with an inwardly extendingintegral armature forming a movable contact, which plate is part of thesealed contact device shown in FIGS. 1 and 2.

FIG. 4 shows a diagrammatic view of one form of multiple contact lightcurrent electromagnetic relay in- United States Patent ice corporating apair of scaled contact devices of the type shown in FIGS. 1 and 2,

FIG. 5 shows a diagrammatic part-sectioned side view of another form ofrelay incorporating two pairs of scaled contact devices,

FIG. 6 shows a diagrammatic part-sectioned plan view of a form of relayincorporating two pairs of scaled contact devices in a differentarrangement to that shown in FIG. 5 and mounted on a printed wiringboard,

FIG. 7 shows a side view of the relay and printed wir ing board shown inFIG. 6,

FIG. 8 shows a diagrammatic part-sectioned side view of a form of relayincorporating two pairs of scaled contact devices in yet anotherarrangement different from those shown in FIGS. 4 to 7, and

FIG. 9 shows a diagrammatic part-sectioned view of a relay including apair of scaled contact units arranged differently to the pairs shown inFIGS. 4 to 8.

Referring now to FIGS. 1, 2 and 3, a mild steel annulus 10 has anickel-iron tube 11 secured within its central aperture by an annularseal 12, for example, of glass. The tube 11 provides a fixed contactmember and magnetic pole-piece, with its annular end face 13 forming oneof two co-operating contacts. The other, movable, contact is formed byan inwardly extending armature integral with a flat resilient plate 14of electrically and magnetically conductive material, such as anickel-iron alloy, which is secured at its periphery to the annulus 10by means of a cap 15 which is itself sealed around its periphery to theannulus 10. A spring ring 16 ensures that when the plate 14 is in theunstressed state a suitable iso lating gap remains between the centralcontact-making area of the plate 14 and the co-operating end face 13 ofthe tube 11. The plate 14 is provided with a number of slots 17, oflength much greater than their width, that serve to increase theresiliency of the plate and thus to reduce the stress necessary todistort it to make contact with the co-operating contact surface 13. Theslot 17 are in the form of arcs of circles and are so interconnectedthat the central contact-making area 18 of the plate 14 is connectedwith its peripheral area 19, by which it is secured to the annulus 10 bythree tongues of metal 20', of width small relative to their length. Thecap 15 may be made of an insulating material (e.g. ceramic) or-metal. Itis preferable to make it of ferromagnetic material, e.g. ferrite or amagnetic metal, as this will serve to increase the effective flux in theair gap between the armature and the fixed contact and so improve theefficiency of the device. The tube 11 is sealed off at the end 21 remotefrom the contacts. The sealing-off of the tube 11 may be performed atany stage during the manufacturing process. The terminals of the deviceconsist of contact pins (not shown) afiixed to and projecting from theannulus 10 and the tube 11.

The device described above thus includes a hermetically sealed enclosurewhich is partly in the shape of a shallow circular cylinder, in whichthe plate 14 and the tube 11 are sealed into the enclosure, the plate 14being in a diametrical plane of the cylinder and the tube 11 being onthe axis of the cylinder. This type of sealed contact device isdescribed in our British Patent Application No. 10571/65 (H.S. Woodhead,Case 4). Corresponding to US. Patent No. 3,331,040.

FIG. 4 shows a pair of sealed contact devices 41, 42 of the type shownin FIGS. 1 and 2 arranged with the two respective fixed contactsparallel and adjacent to each other. A single energising coil 43surrounds both fixed contacts and a C-shaped magnetic yoke 44 completesthe magnetic circuit for the two sealed contact devices as shown. Themain magnetic flux paths through the two devices, that is through thefixed contact and the movable contact of each device, are in series, andthe magnetic yoke couples the movable contacts of the two devices. A

FIG. 5 shows two pairs of sealed contact devices, each pair arrangedwith the two respective fixed contacts coaxial and the two pairsarranged end to end. Two energising coils 51, 52 each surround one ofthe pairs of fixed contacts and are connected in series. The sealedcontact devices and the coils may be held together in the arrangementshown in a moulding, and contact pins 53 may be used for mounting therelay e.g. on a printed wiring board. The main magnetic flux pathsthrough all four devices are in series.

Referring now to FIGS. 6 and 7 two pairs of scaled contact devices arearranged side by side with the two respective fixed contacts of eachpair coaxial. Two energising coils 61, 62 each surround one of the pairsof fixed contacts and are connected in series although parallelconnection is also possible. Two plates 63, 64 of low reluctancemagnetic material each lie alongside the circular face of the enclosure,opposite the fixed contact member, of one of the sealed contact devicesof one pair and the corresponding face of the enclosure of one of thesealed contact devices of the other pair. If these circular faces of theenclosures are not made of electrically insulating material then theplates 63, 64 must be electrically insulated from the circular faces byother means. Each plate magnetically couples the movable contacts of twoof the sealed contact devices as shown. The relay may be held togetherby the two plates being stuck to the sealed contact devices, or theplates and the sealed contact devices may be held together in amoulding.

FIGS. 6 and 7 illustrate how the relay just described can be employed ina crosspoint switching array such as can be used in telephone switchingequipment. A number of relays are arranged in a co-ordinate matrix andmounted on :a printed wiring board on which is printed some of thewiring required for multiplying the crosspoints. It is assumed that afour-wire path through the matrix is to be established at each switchingoperation. The printed wiring board has parallel contuctors printed onone side in groups of five and the relays are mounted on the other sideof the board in rows, each row associated with one group of fiveconductors. FIGS. 6 and 7 show a portion of the printed wiring board 70,with one group of five parallel conductors 71 on one side and one relay,the one described in the previous paragraph, mounted on the other sideby contact pins extending from the two ends of the double energisingcoil, from the four fixed contacts and from the four plates carrying themovable contacts. The four contact pins 72 from the four fixed contactsextend through the board and are soldered to four of the five parallelconductors 71 on the other side of the board which are the inputconductors to the row of relays. In each row, the sealed contact devicesof the relays occupying the same numerical position are connected to thesame conductor 72. The four contact pins 73 from the movable contactsextend through the board and are connected one to each of four outputconductors (not shown) which may be in the form of conventional wiringor ribbon cable. The relays occupying the same numerical position ineach row are connected to the same group of four output conductors. Acontact pin 74 from one 0nd of the double energising coil extendsthrough the board and is soldered to the fifth one of the five parallelconductors 71 on the other side of the board. This end of the doubleenergising coil for each relay in the same row is connected to the sameconductor. A contact pin 75 from the other end of the double energisingcoil extends through the board and is connected to a conductor in theform of conventional wiring or part of the same ribbon cable carryingthe four output conductors. The double energising coils of the relaysoccupying the same numerical position in each row are connected to thesame wire or ribbon cable. As an alternative to the use of conventionalwiring or ribbon cable, it would be possible for the board to haveprinted wiring on both sides and provide all the conductors necessaryfor the switching arra FIG. 8 shows two pairs of scaled contact devices,each pair arranged with the two respective fixed contacts coaxial, andthe two pairs arranged end to end. A single energising coil surroundsboth pairs of scaled contact devices. The sealed contact devices and thecoil may be held together in the arrangement shown in a moulding andconnected to contact pins 81 which may be used for mounting the relaye.g. on a printed wiring board. It will be seen that this arrangement issimilar to that of FIG. 5 apart from the coil arrangement.

In the relays described so far, the pair or pairs of sealed contactdevices have each been arranged with the two fixed contacts next to eachother so that a single energising coil can surround both fixed contacts.It would be possible, however, to have the sealed contact units facingthe other way round. FIG. 9 shows a pair of scaled contact unitsarranged with the enclosures back-to-back. There are two energisingcoils 91, 92, one for each device, and a C-shaped magnet yoke 93coupling the two fixed contacts.

The arrangements of sealed contact devices in a multiple contact relaywhich have been described above, whereby the main magnetic flux pathsthrough all the devices, that is through the fixed contact member andthe movable contact of each device, are in series, benefit the operatingcharacteristics of the relay. One advantage of this arrangement is thatthe operation of the most sensitive contact device reduces thereluctance of the magnetic circuit of the relay and thereby increasesthe magneto-motive force available for the operation of the remainingdevices. The result is cumulative and results in a narrow spread ofoperating characteristics, narrower than the spread found with theindividual single contact devices. There is a similar improvement in therelease characteristics. The first device to release increases thereluctance of the magnetic circuit and thus assists the release of themore sensitive devices.

The sealed contact devices used in relays according to this inventionneed not be the same as the device shown in FIGS. 1 to 3. Contactdevices which are the most suitable should have the following generalcharacteristics. A hermetically sealed enclosure, a flat resilient plateof electrically and magnetically conductive material sealed into theenclosure around a peripheral area and having an inwardly extendingintegral armature which forms a movable contact member, and a fixedmember of magnetically and electrically conductive material sealed intothe enclosure to provide a contact member and magnetic pole piececo-operating with the movable contact member. Other examples of thistype of scaled contact device are described in our British applicationNos. 18874/63 (C. H. Foulkes 33), 37923/63 (E. R. Myatt 15-1). 32741/65,32742/65 and 32743/65 (E. R. Myatt 15-1 Div. A, Div. B and Div. C). Itis preferable, but not essential, with this type of sealed contactdevice to have part of the hermetically sealed enclosure formed by a capof ferromagnetic material which covers one side of the flat plate andprovides a further flux carrying non contact making member forincreasing the effective flux in the air gap between the armature andthe fixed contact.

Within the scope of this type of sealed contact device, it is mostsuitable for the purposes of this invention to have the sealed enclosurewholly or partly in the shape of a shallow circular cylinder, with theflat plate in a diametrical plane of the cylinder, and the fixed contactmember on or parallel to the axis of the cylinder. The sealed contactdevice shown in FIGS. 1, 2 and 3 has the enclosure partly in the shapeof a cylinder and a tube on the axis of the cylinder which completes theenclosure. Certain of the sealed contact devices described in theapplications mentioned in the previous paragraph have a sealed enclosurewholly in the shape of a cylinder with the fixed contact member being asolid rod sealed into one wall of the cylinder and on the axis of thecylinder; in devices of this type the contact area of the movablecontact need not necessarily be at the centre of the fiat plate and sothe fixed contact member could be parallel to the axis of the cylinderrather than on the axis.

It is to be understood that the foregoing description of specificexamples of this invention is made by way of example only and is not tobe considered as a limitation on its scope.

What is claimed is:

1. A multiple contact light current electromagnetic relay including aplurality of sealed contact devices; each sealed contact deviceincluding a hermetically sealed enclosure at least partly in the shapeof a shallow circular cylinder; a fiat resilient plate of electricallyand magnetically conductive material sealed into the enclosure around aperipheral area and having an inwardly extending integral armature whichforms a movable contact member in a diametrical plane of the cylinder;at fixed member of magnetically and electrically conductive materialsealed into the enclosure in parallel to the axis of the cylinder toprovide a contact member and a magnetic pole piece cooperating with themovable contact member; said sealed contact devices including at leastone pair of sealed contact devices arranged so that the main magneticflux paths through all the devices, that is through the fixed contactmember and the movable contact member of each device,

are in series, each pair of contact devices being arranged so that thetwo respective fixed contact members are parallel; a magnetic yoke whichcouples the movable contact of one sealed contact device in a pair ofsealed contact devices; and at least one energizing coil, external tothe enclosures, surrounding the fixed contact members.

2. A relay as claimed in claim 1 in which a first and second pair ofsealed contact devices are arranged side by side with the fixed membersof the first pair parallel to the fixed contact members of the secondpair, in which an individual energizing coil surrounds each pair offixed contact members, and in which there are two plates of lowreluctance magnetic material, each plate lyin-g alongside the circularface of the enclosure, opposite the fixed contact member, of one of thesealed contact devices of the first pair and the corresponding face ofthe enclosure of one of the sealed contact devices of the second pairand magnetically coupling the movable contacts of these two sealedcontact devices.

References Cited UNITED STATES PATENTS 3,293,502 12/1966 Beierle 335152X 3,331,040 7/1967 Woodhead 335-154 X BERNARD A. GILHEANY, PrimaryExaminer R. N. ENVALL, 111., Assistant Examiner

